Emission Of Sm3 Research Articles

Samarium Ions Doped Yttrium Aluminium Garnet Glass Ceramics

Sm3+doped YAG glass ceramics containing single phase of YAG micro-crystals have been obtained by heat-treating the aluminosilicate precursor glasses. The YAG crystals grow with several preferred orientations and a dominant one (444) in the matrix, and present microcrystal sizes in the range of 3~15µm. The pilotaxitic texture existed in internal network of the YAG glass ceramics can increase yield strength and tensile strength of the sample effectively. Typical visible transition emissions of Sm3+have been observed in the YAG glass ceramics under the excitation of short-wavelength visible light, and the spectral intensity ratio between the electric dipole4G5/2→6H9/2and the magnetic dipole4G5/2→6H5/2transitions is lower than the values reported in the optical glasses specifying the enhanced symmetric nature in the Sm3+doped YAG glass ceramics. The obvious Stark splitting exhibited in emission spectrum manifests that rare-earth ions have been incorporated into YAG lattices.

Luminescence Properties of Electron Trapping Material CaB<sub>4</sub>O<sub>7</sub>:Sm<sup>3+</sup>

A novel electron trapping material of CaB4O7:Sm3+ was synthesized by high temperature solid-state reaction, and its characterization and luminescent properties were investigated at room temperature. The results indicate that ultraviolet light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 556, 596 and 643 nm were detected. The photo-stimulated emission spectrum was three bands peaking at 562, 599 and 646 nm that are the characteristic emission of Sm3+ ions due to the f→f transitions 4G5/2→6HJ (J = 5/2, 7/2, 9/2), respectively. The TL glow curve contains two overlapping glow peaks at around 541 and 598 K.was synthesized by high temperature solid-state reaction, and its characterization and luminescent properties were investigated at room temperature. The results indicate that ultraviolet light can be used as exciting source to store energy. After exposed under ultraviolet, the sample was stimulated by 980nm laser. As a result, an obvious luminescence at 556, 596 and 643 nm were detected. The photo-stimulated emission spectrum was three bands peaking at 562, 599 and 646 nm that are the characteristic emission of Sm3+ ions due to the f→f transitions 4G5/2→6HJ (J = 5/2, 7/2, 9/2), respectively. The TL glow curve contains two overlapping glow peaks at around 541 and 598 K.

Fluorescence enhancement in Sm3+/TiO2 nanocrystallites doped PVP matrix

The hybrid matrix containing TiO2 nanocrystals and Sm3+ ions prepared by the non hydrolytic sol–gel method, displays the characteristic emission of Sm3+ ions at the excitation energy corresponding to the energy gap of the TiO2 nanocrystals. On the other hand, emission of Sm3+ was too weak to be observed for the sample containing Sm3+ ions alone. The structural and optical analyses of the samples were carried out using X-ray diffraction technique, transmission electron microscopy, Raman spectroscopy and emission spectroscopy. The TEM image of the sample shows that the TiO2 nanocrystals are well dispersed in the PVP matrix and the XRD confirms the anatase phase of the TiO2 nanocrystals. The enhancement of the Sm3+ emission is attributed to the energy transfer from the TiO2 nanocrystals to Sm3+ ions.

Microstructure and Optical Properties of Sm3+ Doped TiO2 Thin Films by Oblique Angle Deposition

TiO2: 2%Sm3+ thin films were prepared by oblique angle deposition. X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis-NIR spectrophotometer, fluorescence spectrophotometer was employed to characterize the structure and optical properties of TiO2: 2%Sm3+ thin films. The results indicated that these thin films were with anisotropic columnar structure before and after calcination. The optical anisotropy measured by transmission difference (Tp-Ts) at 500nm was increasing from 8% to 33% with calcination. Under ultraviolet excitation (λex = 330nm) and commercial 365nm UV lamp excitation, these TiO2: Sm3+ thin films show intense 4G5/2→ 6H5/2, 7/2, 9/2 emissions of Sm3+. The polarized photoluminescence was anticipated in the anisotropic thin films.

Optical evaluation of multichannel radiative transitions originating from G45/2 level of Sm3+ in heavy-metal-gallate glasses

Conventional visible and novel infrared (IR) emissions of Sm3+ in heavy-metal-gallate glasses (Li2O–K2O–BaO–PbO–Bi2O3–Ga2O3, LKBPBG for short) with low phonon energy have been observed. Judd–Ofelt parameters Ω2 (3.00×10−20 cm2), Ω4 (5.19×10−20 cm2), and Ω6 (1.69×10−20 cm2) indicate a higher asymmetry and stronger covalent environment in the optical glasses. For the visible fluorescence bands peaked at 564, 601, 648, and 710 nm, the maximum stimulated emission cross-sections (σe) were derived to be 1.35×10−22, 9.21×10−22, 9.58×10−22, and 3.91×10−22 cm2, respectively, the values are larger than those in phosphate, oxyfluoroborate, tellurite, and calibo glasses obviously. The observed 1185 nm IR emission lies in the low-loss window of telecommunication system, and the maximum value of σe for this band was obtained to be 6.09×10−23 cm2. The characterization of multichannel radiative transitions of Sm3+ in LKBPBG glasses is beneficial in exposing its potential applications in visible and IR optoelectronic devices.

PREPARATION AND FLUORESCENCE PROPERTIES OF SAMARIUM COMPLEXES CONTAINING POLYARYLETHERKETONES BEARING PENDANT CARBOXYL GROUPS

The carboxyl-containing polyaryletherketones (PEK-1,PEK-2 and PEK-3) with excellent thermal properties and good film-formations prepared in our group were used as macromolecular ligands. Using 1,10-phenanthroline (Phen) as co-ligand and samarium ( Sm3 + ) as the central ion,a series of novel samarium coordination polymers (PEK-Sm3 + -Phen) were prepared. The FTIR and UV-Vis absorption spectra suggested that both the oxygen atoms of carboxyl groups of PEK and the nitrogen atoms of Phen were coordinated with Sm3 + ions. The XRD curves indicated Sm3 + ions could distribute homogeneously within the polymer matrix due to the formation of coordination bonds between Sm3 + and the carboxyl groups of PEK. The fluorescence spectra showed that all the coordination polymers obtained could exhibit the intense characteristic emission of Sm3 + ions under UV excitation. Moreover,their emission intensities were much higher than that of the corresponding small molecular complex ( Sm3 + -Phen) due to the introduction of PEK with the rigid polymer chain,which could result in the stable coordination structure and the low coordination symmetry around Sm3 + ion in the PEK-Sm3 + -Phen system. In addition,among the three coordination polymers obtained,PEK-1-Sm3 + -Phen showed the highest fluorescence intensity. The emission intensity of PEK-1-Sm3 + -Phen could reach a maximum value at the Sm3 + content of 15. 73 wt%.

Orange‐red upconversion luminescence of Sm3+‐doped ZnO‐B2O3‐SiO2 glass by infrared femtosecond laser irradiation

Abstract— Near‐infrared‐to‐visible upconversion luminescence was observed in Sm3+‐doped ZnO‐B2O3‐SiO2 glass under femtosecond laser irradiation. The luminescence spectra show that the upconversion luminescence originates from 4G5/2 to 6Hj/2 (j = 5, 7, 9) transition of Sm3+. The dependence of the fluorescence intensity of Sm3+ on the pump power indicates that a two‐photon absorption process is dominant in the conversion of infrared radiation to the visible luminescence. The analysis of the upconversion mechanism reveals that the simultaneous absorption of two infrared photons produces the population of upper excited states, which leads to the characteristic orange‐red emission of Sm3+. A three‐dimensional display is demonstrated based on the multiphoton absorption upconversion luminescence.

Polarized Luminescence Properties of TiO2:Sm3+ Microfibers and Microbelts Prepared by Electrospinning

One-dimensional TiO2:xSm3+ microfibers and microbelts were prepared by electrospinning. X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), electron paramagnetic resonance (EPR), and polarized luminescence measurements were performed to characterize these TiO2:xSm3+ microfibers and microbelts. SEM and HRTEM results indicate that TiO2:xSm3+ microfibers calcined at different temperature are belt-like. The average width and thickness of TiO2:xSm3+ microbelts calcined at 700 °C is about 1.0 and 0.4 μm, respectively. Under ultraviolet excitation (λex = 330 nm) and commercial 365 nm UV lamp excitation, these TiO2:xSm3+ microbelts show intense 4G5/2 → 6H5/2,7/2,9/2 emissions of Sm3+ ions. Polarized luminescence measurement confirms that the luminescence of single TiO2:xSm3+ microbelt is linear polarization.

Self-quenching of spontaneous emission in Sm3+ doped lead-borate glass

The lifetimes of Sm 3+ doped in a binary glass are studied as a function of the complex refractive index of the glass. The local field effect has been taken into account and a real cavity around the emitter is assumed. The results are analyzed in the framework of the quantum electrodynamical equation to obtain a parameter that is related to the radius of cavity around Sm 3+ . The knowledge of this parameter is crucial in tailoring the lifetimes and has been found to be 1.48 nm.

Emission of Rare Earth Ions Incorporated into Metal Oxide Thin Films and Fibres

ABSTRACTPhotoluminescence (PL) of undoped and Sm-doped TiO2, ZrO2and HfO2thin films and fibers was investigated at temperatures ranging from 6 to 300 K. The thin films were grown by the atomic layer deposition (ALD) technique and doped by using the ion implantation method. The fibers were prepared by using the sol-gel method whereas anin-situdoping was used to obtain the required concentration of Sm3+ions in the films. In undoped as well as doped materials, PL was efficiently excited via band-to-band transitions. The emission of undoped materials was attributed to the radiative recombination of self-trapped excitons (STE). In doped materials, intense emission of Sm3+was recorded. It is proposed, that there exists a concurrence between the radiative recombination of bound excitonic states and the energy transfer to Sm3+ions, particularly at lower temperatures.

Theoretical manifestation of the shell model for energy transfer

Luminescence decay curves for the 4G5/2→6H7/2 emission of Sm3+ in the hexachloroelpasolite crystals Cs2NaSm0.01Gd0.99Cl6 and Cs2NaSm0.01Eu0.1Y0.89Cl6 have been measured over the temperature range 10–300 K using pulsed laser excitation into the magnetic-dipole allowed 6H5/2→4G5/2 electronic transition of Sm3+. The emission is quenched by cross relaxation to nearby Sm3+ ions and energy transfer to the 5D0 state of Eu3+ acceptors and the decay curves are analyzed using a recently developed shell model for energy transfer. The corresponding energy-transfer rate to a single Eu3+ acceptor at a distance R1=7.65 Å shows a rapid increase in the temperature range 200–300 K which is explained in terms of the thermal population of the initial Sm3+(4G5/2)Γ7 donor state and the Eu3+(7F1)Γ4 acceptor state. The near-resonant magnetic dipole–magnetic dipole contribution to the total energy-transfer rate between a Sm3+ donor ion and a nearest-neighbour Eu3+ acceptor is calculated. We show the applicability of the shell model for the simultaneous treatment of cross-relaxation and energy-transfer processes to the 4G5/2 decay kinetics of Sm3+ in a cubic lattice.

Luminescence and energy transfer of rare-earth-metal ions in Mg2Y8(SiO4)6O2

The photoluminescence of Ce3+, Tb3+ and Sm3+, and energy transfer from Ce3+ to Tb3+, Dy3+ and Sm3+ in Mg2Y8(SiO4)6O2 are reported and discussed. The Ce3+ ion shows blue luminescence under UV excitation, and occupies simultaneously the 4f site and 6h site in the host lattice. The optimum concentrations for the 5D3 and 5D4 emissions of Tb3+ and the 4G5/2 emission of Sm3+ are determined to be 0.04, 0.20 and 0.10 mol in every mol of Mg2Y8(SiO4)6O2, respectively. The critical distances responsible for the cross-relaxation between the 5D3–5D4 and 7F6–7F0 transitions of Tb3+ and between the 4G5/2–4F9/2 and 6H5/2–4F9/2 transitions of Sm3+ are estimated to be 1.43 and 1.06 nm, respectively. Both Tb3+ and Dy3+ can be sensitized by Ce3+, but Ce3+ and Sm3+ quench each other.